We had some issues on our US East servers again overnight. They've been restarted and are functioning normally now.
Code:
registercloudguest
should get you back online with updates, now.

The issues in US East haven't gone unnoticed; in fact both US East update servers have been rebuilt 3 times; we're doing some pretty intensive logging at every level, from Apache down to packet analysis, and will find the solution. It bears noting that our update servers in US East are the _only_ servers we've had to rebuild more than once, and servers bearing significantly more load in other regions/providers have not had the same issues.